The invention relates to an apparatus for producing a three-dimensional object from a powder material which comprises powder particles and is solidifiable by electromagnetic radiation, comprising support means having a substantially plane support surface for supporting said object, means for applying a layer of said powder material to said support surface and radiation means for selectively exposing said material to electromagnetic radiation at places corresponding to said object. The invention further relates to a method of layerwise producing a three-dimensional object by generating a layer of such a powder material, and solidifying said layer by selective exposure to electromagnetic radiation at places corresponding to said object. The invention further relates to an apparatus for applying a layer of such a powder material to a substantially plane surface comprising a receptacle for said powder material, said receptacle being disposed above said surface and having a bottom side facing said surface, an outlet aperture having an aperture width provided in said bottom side and means for displacing said receptacle across said surface and substantially parallel thereto.
An apparatus and a method for producing a three-dimensional object by selective laser sintering is disclosed for example in U.S. Pat. No. 4,863,538. A predetermined amount of powder material is dumped onto a lowerable base and equally distributed thereon by means of a roller travelling across the base while rotating in a direction opposite to the travelling direction. Thereafter the distributed material is exposed to radiation at those places of the formed material layer which correspond to the object whereby the material is sintered or baked together thereat.
WO 95/18715 discloses an apparatus and a method for producing a three-dimensional object as above defined and likewise an apparatus for applying a layer of a powder material to a substantially plane surface as inicially defined. The applying or coating device disclosed in WO 95/18715 has a wide lower outlet aperture. This gives rise to the problem that the dead weight of the powder discharged from the powder receptacle generates forces acting on presolidified sintered portions in the production area and causing a displacement thereof within the powder bed. To prevent this effect the sintered portions must be tied to the construction base, for example using a support structure (support) which is not part of the object to be formed and must be removed at the end of the production process. This increases the production time and reduces production quality. Moreover, the production of the support requires time.